Deadlock Detection | Should the node T4 point to T1 and T2?

This example regarding deadlock detection was shown during one of my lectures and I have a doubt about it. The image is shown below.

For deadlock detection mechanism, why does T4 point only to T2 and not T1? Chronologically, T1 requests for the exclusive lock before T4. So shouldn’t T4 point to T1 as well?

Dependency Graph