The three women were suspicious to hear a male voice coming from Devin's kitchen, knowing that Devin's best friend was on the run.
Devin was nervous, not wanting to ruin Robin's surprise for Sabrina.
"It's nobody, just me."
Matilda was suspicious because when she spoke with Devin on the phone, she heard him talking to someone and thought that her mind was playing games on her.
It was the reason why she came without informing him with the excuse that she wanted to pick her working clothes for tomorrow, having Sabrina and Lizzy tagging along because they were bored.
She quickly rushed to the kitchen and seeing Robin, she froze, as he pressed his finger on his lips.
Matilda guessed that Robin was learning to cook to impress Sabrina like Daniel did for Lizzy, but was worried about the discoloration on his hand, which must be from a burn he sustained, for which reason he screamed.