Episode title would literally translate as "Time on their heels". This is a play on Hitchsock's North by Northwest (1959)'s Spanish title ("Death on his heels")
In the scene in which Amelia and Alonso first go to San Sebastián, they are surrounded by birds and she is dressed in a similar way and color as Tippi Hedren in The Birds (1963).
The first scene in the Ministry of Time mimics the opening scene of Rear Window, specially the text in L.B. Jefferies' casket, photos on the wall and camera moves.
Irene says she has cut herself preparing gazpacho. This is a reference to actress Cayetana Guillén Cuervo's frequent kitchen accidents during her participation in MasterChef Celebrity (2016) shortly before the shooting of Season 3.