The grenade *spoiler*
After he escapes from Agnieska's appartment and he was chased by cars, he dropped a nade. Where did that nade come from ?
... I mean it's not like you can say "I always have a nade with me - never leave home without it". Plus, even if he would have, I am pretty sure it'd have rolled out when he tumbled on either the rug (jumping through the balcony window of the adjacent building) or on the bazzar small metal roofs at night (as his foot went a bit through one of them).
... unless I missed something.