confused! what's the difference between them ?

[billy]

hello,

need you help with these two sentences below:

1 The outer door doesn't lock, somebody could've walked in at any point

2 The outer door doesn't lock, somebody could walk in at any point


besides, what does it mean by "at any point " ?


thank you in advanced

[Tdol]

Inthe first, the situation is no longer true- no one can walk in now. In the second, they still could.'At any point' means 'at any time'.