If you take my advice you'll see Mr.Ackroyd.' In her agitation Lydia could not reflect upon the complicated details of the case.

She never doubted that Totty knew the truth; in this, we know, Luke had unintentionally deceived her.

Perhaps the advice to consult Ackroyd was good; perhaps he had learned something more since Wednesday night, something that Totty also knew but did not care to communicate herself.
'I'll try and find him,' Lydia said.

'But if you do hear any thing you wouldn't keep it from me ?' 'You'll hear just as soon as I do,' was the reply.
Lydia turned away, feeling that the girl's coldness was a cruelty, wondering at it.

She herself could not have behaved so to one in dire need.
She was going away, but Totty stopped her.
'You can't go back like that, in the rain.