It doesn't work that way. Conflicts are resolved before any transfer starts. The flow is:
Scan both sides and compare (compute file hashes or just compare mtime, no data transferred)
Show conflicts if any → you resolve them
Show copy/delete summary → you approve
Only then does the actual transfer begin. So you never come back to find it halted mid-transfer. All decisions happen upfront while it's just reading metadata, which is fast even for large trees.