That sounds like after that Germans had no other option but appologize and quitely leave back for Germany...
How did you draw such a conclusion?
After that German 4th Panzer-Division had no option but to entrench itself on the western outskirts of Warsaw, hoping for arrival of reinforcements. In the meantime they were towing away damaged tanks and trying to repair them (one of field workshops was located in the town of Mszczonow - which however got overran by Polish 31st Infantry Regiment on 11 September and already damaged tanks gathered there, awaiting for renovation, once again suffered).
The first unit which reinforced 4th Panzer-Division on its defensive positions on the outskirts of Warsaw, was 31st Infanterie-Division.
Between 10 and 13 September they also had to defend against Polish attacks carried out by garrison of Warsaw and by Army "Lodz" withdrawing towards Warsaw and Modlin from the western direction (being pushed back by German 8th Army, which however got attacked by Polish Army "Poznan" at the Bzura).
Regarding Warsaw:
Warsaw surrendered on 28 September, so after three weeks since the first German attempt of capturing it.
Perhaps Germans might have been able to force the capital of Poland to sign capitulation earlier, if not the battle of Bzura taking place. But Warsaw surrendered mostly because of hopeless overall situation of Poland, rather than lack of capabilities of further defence. Warsaw could be defended longer than until 28 September - it had the necessary forces and the necessary resources. But that would cost huge number of civilian casualties among its inhabitants.
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In Mszczonow on 11.09.39 Polish 31st Inf.Rgt. overran rear units (including a repair workshop of Pz.Rgt.36.) of 4th and 1st Panzer-Divisions:
Germans lost ca. 340 Zugkraftwagen (Zgkw) in Poland in 1939 - such as these ones, photographed in Mszczonow after the battle:
And here a Panzer IV tank destroyed in Mszczonow on 11.09.39 during the Polish assault:
It was destroyed in the morning by direct fire of Polish cal. 75 mm type 02/26 field gun from infantry support artillery platoon of 31st Kaniowski Infantry Regiment. Gun was commanded by corporal Świerczyński and firing was being supervised by regimental aide-de-camp - captain Ogrodnik:
Panzer II sidenumber "145" wrongly described as destroyed in Warsaw (in fact it was destroyed in Mszczonow on 11.09.1939):
The same Panzer II - "145" - photo taken in Mszczonow after the battle (and a killed soldier from its crew):
And this is one of my favourite tank wrecks photos - "534" from Pz.Rgt.35 destroyed near Ruszki - Adamowa Góra on 16.09.39 (battle of Bzura):
Panzer IV from 1st Panzer-Division destroyed near Kiernozia (during the battle of Bzura) on 16.09.1939:
This one belonged to Hauptmann Werner von Köckritz:
Nachname: von Köckritz
Vorname: Werner
Dienstgrad: Hauptmann
Geburtsdatum: 09.12.1909
Geburtsort: Berlin
Todes-/Vermisstendatum: 16.09.1939
Todes-/Vermisstenort: bei Kiernozia
And another Panzer IV destroyed near village Skowroda (near Kiernozia) on 17.09.1939 (during the battle of Bzura):
This Panzer IV belonged to Leutnant Jost from 1st Panzer-Division:
Nachname: Jost
Vorname: Franz
Dienstgrad: Leutnant
Geburtsdatum: 27.02.1915
Geburtsort: Hamburg
Todes-/Vermisstendatum: 17.09.1939
Todes-/Vermisstenort: Skowroda
And such a Panzer II from 1st Panzer-Division nicely knocked out near Kiernozia:
Here a Panzer II knocked out by Polish cavalry (Wolynska Cavalry Brigade) in the battle of Mokra-Ostrowy (01.09.39 - 02.09.39):