Filming resumed in London this week, and in this clip you see Cruise attempt to leap onto the ledge of a window ... but he slips on something before he gets out.

A cameraman on the scene says the actor was later seen using crutches, but there are no pics and we haven't confirmed.

It's strange -- Tom appeared to have nailed this exact scene last week, unclear why he did it again. As we reported ... he's fresh off a broken ankle from a failed jump on the set last year.

We've got a call in to Tom's camp for an injury update, but our advice -- let the stuntmen do their thing, Tom. It's all good ... we promise.