When Tyler arrived at Emilia's home, he happened to see Avril (Elle) cleave Charles to death from outside the window.
Although Tyler would have arrived in the nick of time even without Avril and Elle's intervention, he was profoundly thankful for their help in saving Emilia.
However, the current situation seemed somewhat complicated to manage.
From afar, Tyler observed that Emilia appeared to be unwell, with Avril attempting to cool her forehead.
If things continued in this manner, Emilia and Avril might become exceedingly good friends. Then, it would only be a matter of time before they started discussing their romantic interests, potentially exposing Tyler's "romantic entanglement" with two of them.
(Silly Nissen: Two? It's not just two boats you're juggling, Tyler. I see you're destined to command a fleet.)