A definition of a phrasal verb slip through, is "to fail to be noticed, resulting in problems", and the definition of a verb slip is "to go somewhere or put something somewhere quickly, often so that you are not noticed".
Here goes a sentence:
"He slipped quickly through the door, though not quickly enough to prevent himself from being caught by a guard."
The question is: Is the second part of the sentence necessary/mandatory to make it clear that the verb is a phrasal one and not a verb with a preposition? Since he failed to slip through the door quickly, he was caught.
Omitting everything that is after the comma, can we use a verb "pass" to mean to go through the door?
He passed through the door.